The '+' glyph in the chat input toolbar button is not visually centered within its button - it appears offset rather than aligned to the center.
Steps to reproduce:
- Open the Chat view.
- Look at the '+' button in the input toolbar.
Expected: the '+' glyph is centered horizontally and vertically within the button.
Actual: the '+' glyph is off-center.
- VS Code version: (fill in from Help > About)
- OS: Windows

The '+' glyph in the chat input toolbar button is not visually centered within its button - it appears offset rather than aligned to the center.
Steps to reproduce:
Expected: the '+' glyph is centered horizontally and vertically within the button.
Actual: the '+' glyph is off-center.